[Skywise]

There's been a little cluster of quakes off the north end of Japan's main island. As of this writing, six quakes, five in a tight cluster, four of which are M5+. The last four time-wise have occurred within an hour of each other. This is north of the 2011 rupture. Only two have depths at the moment, 20km and 26km. Tohoku's hypocenter was at 29km. I wonder if the 'next segment' of the subduction zone might be thinking of letting loose? A 'cascade failure'?

Might be nothing, too. I'm sure seismologists in Japan are watching very closely.

Brian